This invention relates to mirrors for automobiles, and particularly to a device to provide resistance to movement of a side-view mirror so that once set in a particular position, the mirrors will stay in that position until manually adjusted again.
A number of automobiles on the road, in particular pick-up trucks of various makes and models and other vehicles made from pick-up truck platforms, such as sport-utility vehicles (SUVs), have side-view mirrors like those shown in FIG. 1. As shown in FIG. 1, an exemplary side view mirror assembly 10 comprises the mirror housing 12, a shaft 14, and a mirror assembly mounting bracket 16 that attaches to the truck body 18. Grommets 20a and 20b, such as made of rubber or the like, typically are mounted on either end of the shaft at the interfaces with the mirror housing and mounting bracket, respectively. Sometimes one or both of grommets 20a and 20b may become lost, or the portion of the grommet that protrudes from the recess 21 in mounting bracket 16 into which shaft 14 is inserted, may become torn off.
The side-view mirror is typically set in one place by a driver depending upon his or her height and preference for how to view the road. When another driver of a different height or having a different set of preferences drives the vehicle, the other driver may adjust the mirror to a different position by twisting mirror shaft along axis Y, by twisting mirror housing along axis X, or both. Pick-up trucks in particular are frequently used for pulling trailers, such as boats, camping trailers, horse trailers, and the like, requiring the mirrors to be adjusted for the overall length of the vehicle with the trailer, and then back again when the trailer is unhitched. Owners of such vehicles typically keep the vehicles in service for a long time. The repeated movement of the mirrors back and forth may eventually cause wear that makes the mirrors no longer resistant enough to adjustment to keep them from moving on their own as a result of vibration or wind resistance. In addition to being a nuisance for the vehicle owner who has to repeatedly adjust his or her mirror, the inability of the mirror to stay in position may also pose a safety concern. Thus, owners of such vehicles may be forced to entirely replace the mirror assembly, which can be expensive, and somewhat wasteful, since the mirror assembly is otherwise often not in need of replacement, except for the lack of resistance to adjustment.
There is therefore a need in the art for an inexpensive mirror tensioning device that can be placed on an existing mirror assembly to increase resistance without having to entirely replace the mirrors.
In accordance with this invention, there is provided a tensioner to provide resistance to rotation of a shaft relative to a surface from which the shaft originates. The tensioner comprises a shaft collar split into at least two pieces; at least one connector for fastening the split pieces of the shaft collar together about the shaft; and a bushing split into at least two pieces. The bushing is adapted to contact an interface between the shaft and the surface from which the shaft originates. At least a portion of the bushing is adapted to fit coaxially inside and be radially constrained by the shaft collar. At least one axially adjustable member, such as a set screw, corresponding to each bushing piece and having a corresponding axial guide within the shaft collar is insertable within the corresponding axial guide and adjustable to exert pressure upon the bushing to push the bushing into or against the interface. The bushing may comprise a flat surface adapted to press against a grommet at the interface when the axially adjustable member is adjusted to exert pressure upon the bushing. The bushing may also or instead comprise a spacer wedge adapted to be inserted into a recess that comprises the interface between the shaft and surface in the absence of a grommet. The spacer wedge is adapted to be wedged between the shaft and an inner edge of the recess when the axially adjustable member is adjusted to exert pressure upon the bushing. The bushing may be axially reversible for use in the both the configuration with the grommet at the interface or the configuration without the grommet at the interface, and may comprise the flat surface on one axial side and the spacer wedge on an opposite axial side.
The shaft collar may comprise a shaft contact surface that is flat and may be adapted to be installed on the shaft with its axis aligned with the shaft axis. The tensioner may also comprise a shaft contact surface that is convex, the shaft contact surface further protruding from a shaft collar inner surface that is convex. The tensioner having the convex contact surface and convex inner surface may be installed on the shaft with its axis angled relative to the shaft axis. The flat surface of the bushing may extend from an inner radius adapted for contact with the shaft to an outermost radius of the bushing. The flat surface of the bushing may instead extend from the inner radius adapted for contact with the shaft to a ridge having an inner radius greater than an outer radius of the grommet, the ridge adapted to center the bushing on the grommet.
The tensioner may be particularly adapted for installation on a shaft of a side-view mirror of a vehicle, such as a pick-up truck. One embodiment of the side-view mirror tensioner may comprise a shaft collar split into two pieces; at least one connector for fastening the two pieces of the shaft collar together about the shaft; and a bushing split into two pieces. The bushing is adapted to contact an interface between the mirror shaft and the mirror mounting bracket or the mirror shaft and the mirror housing, and is adapted to be axially reversible for use in a configuration having a grommet at the interface or in a configuration having no grommet at the interface, the bushing comprising a flat surface on one axial side and a spacer wedge on an opposite axial side. At least one set screw corresponding to each bushing piece is threaded axially through the shaft collar to make contact with and exert pressure upon the bushing to push the bushing into or against the interface when the set screw is tightened.
The invention also comprises a method for increasing resistance of a shaft to rotation relative to a surface from which the shaft originates. The method comprises installing a tensioner on the shaft, the tensioner comprising a shaft collar split into at least two pieces; fastening means for joining the pieces of the shaft collar together; a bushing split into at least two pieces; and at least one axially adjustable member corresponding to each bushing piece and having a corresponding axial guide within the shaft collar. The method comprises positioning the pieces of the shaft collar and the pieces of the bushing together about the shaft with at least a portion of the bushing placed coaxially within the shaft collar, and the bushing placed adjacent an interface between the shaft and the surface from which the shaft originates. The pieces of the shaft collar are then joined together using the fastening means so that the shaft collar radially constrains the bushing and attaches snugly to the shaft. Finally, the axially adjustable members are axially adjusted within the corresponding axial guides to exert pressure upon the bushing to push the bushing into or against the interface.
In a method where the shaft comprises a mirror shaft for a side-view mirror assembly of a vehicle, the interface may comprise an interface between the mirror housing and the mirror shaft or an interface between the mirror shaft and a mirror mounting bracket on the vehicle, and the bushing may comprise a flat surface on one axial side and a spacer wedge on an opposite axial side. In such case, the method further comprises determining if the interface contains a grommet or no grommet; and aligning the bushing with the flat surface adjacent the interface if a grommet is present, or aligning the bushing with the spacer wedge adjacent the interface if no grommet is present.